G'day all, another RIAA related question that someone might venture an opinion on. As the VSPS is essentially a 'full feedback' op amp design, this particular circuit approach seems to be prone to an issue that I've conclusively proved that happens, that is exaggerated audibility of record scratch etc.
Other phono stages I possess that utilise passive treble equalisation seem to be quite free of this issue. From what I've read this issue seems to be a consequence of transient intermodulation effects in the feedback loop of the op amp voltage amplifier stage.
Other builders of the VSPS have apparently also noted the same issue from what I've read. That's a real pity actually as I rather like the sound of the VSPS, but the exaggerated click audibility is a real turn off in my opinion. Regards, Felix.
Other phono stages I possess that utilise passive treble equalisation seem to be quite free of this issue. From what I've read this issue seems to be a consequence of transient intermodulation effects in the feedback loop of the op amp voltage amplifier stage.
Other builders of the VSPS have apparently also noted the same issue from what I've read. That's a real pity actually as I rather like the sound of the VSPS, but the exaggerated click audibility is a real turn off in my opinion. Regards, Felix.
Find it, something like this would be good enough.. remodeled scheme, I completely forgot that now using positive input ..
How does it compare to the two op-amp version?
May be most of you did read this paper:
Op amps in small-signal audio design - Part 1: Op amp history, properties | EE Times
Op amps in small-signal audio design - Part 1: Op amp history, properties | EE Times
Vulejoy,
I'm interested but confused. You say one chip op-amp, yet your last schematic shows 2 chips. Is that the one you're currently using, and you want to try a single op-amp version with LT1028 alone?
That's right..
I will try single opamp version with LT1028.. I would also try AD797, it should work even better..
@Vulejov,
What about LME49710HA compared to AD797, please.
Low noise..
Thank you very much, I did order several AD797..
My phono is designed for the MC cartridge, so I choose opamp according with that..
I just borrowed VSPS board, because the structure is same and uses a single chip..
PCB have lot of space for RIAA network capacitors.. thinking to use Wima FKP-1, for that purpose small correction of value..
Attachments
Will Use Two Separate Power Supplies: Two separate chassis or just one?
Hello,
Maybe a silly question...
I just ordered a Phonoclone kit! This will be the most challenging project for me so far I´ve just done kits and upgrade kits before with everything included..
I a really looking forward to this job...
I just ordered two chassis from this site in Italy: modushop.biz
I ordered
one chassis 230x230mm ( for the phono clone boards )
and
one chassis : 230x330mm ( for two separate power supplies )
So maybe I messed up, is it possible to install two separate power supplies in one chassis - or will I need two separate boxes?
Hello,
Maybe a silly question...
I just ordered a Phonoclone kit! This will be the most challenging project for me so far I´ve just done kits and upgrade kits before with everything included..
I a really looking forward to this job...
I just ordered two chassis from this site in Italy: modushop.biz
I ordered
one chassis 230x230mm ( for the phono clone boards )
and
one chassis : 230x330mm ( for two separate power supplies )
So maybe I messed up, is it possible to install two separate power supplies in one chassis - or will I need two separate boxes?
Is it worth changing PhonoClone's IC 3&4 as they are in the Power Supply side?
My PC is built to the BoM with the addition of caps on the input sockets and IC PS pins.
Anyone?
Hey Richard
It s been a while I got my turntable rig back up and I started working on my phonocline and vsps again.
Quick question.
C3 value follows the normal coupling rules right? Calculating its value according to the input impedance of your preamp and the time constant / filter you want to use?
Oh and if my preamp is AC coupled, is it ok to omit C3 and R7?
It s been a while I got my turntable rig back up and I started working on my phonocline and vsps again.
Quick question.
C3 value follows the normal coupling rules right? Calculating its value according to the input impedance of your preamp and the time constant / filter you want to use?
Oh and if my preamp is AC coupled, is it ok to omit C3 and R7?
I have (literally) just replaced IC 2, 3 & 4 in my PC3 with LME49710's
Lower noise and clearer music are the first things to hit me.
... and thats 3 seconds into the first track. No brainer at the cost (~£8.00 )
Why didn't you change IC1? I believe IC1 have more impact on the sound.
I use LT1028 in 1 and AD797 in 2. Very nice. I must try the LME49710 in 3 & 4 when I get home.
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